The present invention generally relates to a system and method for the use of low-intensity light therapy alone or in combination with various topical compositions. Various medically beneficial results can be obtained by using combinations of photothermal, photochemical, photodynamic and photomodulatory means and applying a cosmeceutical or drug composition, naturally occuring or synthetic or genetically engineered topical or systemically delivered chromophores, or other light-activated chromophores onto or into mammalian tissue and exposing the composition to electromagnetic radiation.
Low-intensity light therapy is an emerging field of study wherein light emitting diodes and other emitters of low-intensity electromagnetic radiation are used to treat various medical conditions such as acne, hair growth stimulation, hair growth inhibition, scar reduction and removal, wrinkle reduction, etc. This is in stark contrast to prior art approaches that used high-intensity monochromatic light to treat such conditions.
For example, a known technique for hair removal uses a short pulsed laser to produce a wavelength that may be absorbed by a xe2x80x9cforeignxe2x80x9d material or xe2x80x9cskin contaminantxe2x80x9d. Aspects of this technique are described, for example, in U.S. Pat. Nos. 5,423,803, 5,817,089, 5,425,728, 5,226,907, and 5,752,949, all of which are incorporated by reference. This contaminant may be applied directly onto the skin and may be introduced into the empty space surrounding the hair shaft. One contaminant that has been used is carbon graphite in particulate form. The graphite particles have a diameter that is small enough to enable the particles to drop from the surface of the skin into the free empty spaces between the duct and the hair shaft. The energy from a laser may then interact with the contaminant particles. This causes injury to surrounding tissues whose function is to support the growth of the hair shaft. This tends to reduce or eliminate hair growth.
These contaminant particles are not physically incorporated into the hair shaft or into the surrounding hair follicle, hair bulge or hair duct cells. Nor do these contaminant particles chemically, immunologically, biologically or otherwise interact, react or complex with the hair shafts or tissue cells. The contaminant particles simply physically occupy the space surrounding the hair shaft.
Another known hair removal technique is to use a pulsed electromagnetic radiation source to produce a wavelength that may be absorbed by hair, as described, for example, in U.S. Pat. No. 5,683,380, which is incorporated by reference.
There are problems with present light and laser hair removal techniques. Known melanin targeting systems work reasonably well and are reasonably safe only when the color of the hair is very dark and when the skin is very light and not tanned. Virtually all light sources which tend to target melanin are also inherently absorbed by the overlying and surrounding skin. At present, these light sources cannot be safely used at optimal very high power settings for people with darker skin or even people with a dark tan.
In another example, there is a known hair removal process which uses a 1064 nm laser to produce a wavelength that may be absorbed by a skin contaminant appears to be safe on all skin colors, including darker skin colors. However, this safety is a consequence of there being very little melanin absorption. It is therefore necessary to add graphite particles in oil contaminant lotion before laser treatment. This graphite particle lotion does not enter into the hair shaft itself. Instead, the graphite lotion tends to occupy empty spaces surrounding the hair shaft as it sits in the hair duct. This presents a problem. Either an insufficient or sub-optimal number of graphite particles penetrate into the hair duct, or an insufficient amount of damage is caused by the graphite particles. Consequently, many treatments tend to be required before an acceptable result is achieved.
The present invention is to a method for the manipulation of collagen, fibroblast, and fibroblast-derived cell levels in mammalian tissue comprising the steps of exposing the tissue to a plurality of pulses from at least one source of narrowband, multichromatic electromagnetic radiation having a dominant emissive wavelength of from about 300 nm to about 1600 nm, and wherein said pulses have a duration of from about 0.1 femtoseconds to about 100 seconds, the interpulse delay between said pulses is from about 0.1 to about 1000 milliseconds, and the energy fluence received by said tissue is less than about 10 joule per square centimeter.
In another embodiment of the invention, the source of narrowband, multichromatic electromagnetic radiation is selected from a light emitting diode, a laser, a fluorescent light source, an organic light emitting diode, a light emitting polymer, a xenon arc lamp, a metal halide lamp, a filamentous light source, an intense pulsed light source, a sulfur lamp, and combinations thereof, and the dominant emissive wavelength is from about 400 nm to about 1600 nm.
In another embodiment of the invention, the source of narrowband, multichromatic electromagnetic radiation further comprises a filter element for reducing the intensity of infrared radiation received by said tissue
It is preferred that the energy fluence received at the tissue is 1 J/cm2 or less or, alternatively, that the energy fluence received at the tissue is greater than 1 J/cm2 and the tissue is cooled. In another embodiment of the invention, the energy fluence received at said tissue is from about from about 1xc3x9710xe2x88x926 J/cm2 to 1 J/cm2 or, alternatively, the energy fluence received at said tissue is from about from about 1xc3x9710xe2x88x923 J/cm2 to about 0.1 J/cm2.
According to the present invention, pulse length is from about 1 nanosecond to about 1 second and, preferably, the pulse length is from about 5 nanoseconds to about 100 milliseconds.
In an embodiment of the invention, source of electromagnetic radiation is filtered to reduce the energy fluence of infrared radiation or is filtered to reduce the perception by the tissue of radiation having a wavelength greater than about 700 nm.
In another embodiment of the invention, a topical composition may be applied to the skin or target tissue prior to exposure to electromagnetic radiation. The topical composition is selected from the group consisting of naturally occurring chlorophyll-containing compounds, carotenoid-containing compounds, phyocobilin compounds, indocyanine green, methylene blue, rose Bengal, Vitamin C, Vitamin E, Vitamin D, Vitamin A, Vitamin K, Vitamin F, Retin A (Tretinoin), Adapalene, Retinol, Hydroquinone, Kojic acid, a growth factor, echinacea, an antibiotic, an antifungal, an antiviral, a bleaching agent, an alpha hydroxy acid, a beta hydroxy acid, salicylic acid, antioxidant triad compound, a seaweed derivative, a salt water derivative, algae, an antioxidant, a phytoanthocyanin, a phytonutrient, plankton, a botanical product, a herbaceous product, a hormone, an enzyme, a mineral, a cofactor, an antiaging substance, insulin, minoxidil, lycopene, a natural or synthetic melanin, a metalloproteinase inhibitor, proline, hydroxyproline, an anesthetic, chlorophyll, bacteriochlorophyll, copper chlorophyllin, chloroplasts, carotenoids, phycobilin, rhodopsin, anthocyanin, inhibitors of ornithine decarboxylase, inhibitors of vascular endothelial growth factor (VEGF), inhibitors of phospholipase A2, inhibitors of Sxe2x80x94adenosylmethionine, licorice, licochalone A, genestein, soy isoflavones, phtyoestrogens, derivative, analogs, homologs, and subcomponents thereof, and derivatives, subcomponents, immunological complexes and antibodies of said target tissue, and synthetic and natural analogs thereof, and combinations thereof.
In another embodiment of the present method for the manipulation of collagen, fibroblast, and fibroblast-derived cell levels in mammalian tissue, the method comprises exposing the tissue to at least one source of narrowband, multichromatic electromagnetic radiation having a dominant emissive wavelength of from about 300 nm to about 1600 nm for a period of time of from about 10 seconds to about 24 hours, wherein the energy fluence received by said tissue is less than about 10 J/cm2.
It is preferred that the source of narrowband, multichromatic electromagnetic radiation is selected from a light emitting diode, a laser, a fluorescent light source, an organic light emitting diode, a light emitting polymer, a xenon arc lamp, a metal halide lamp, a filamentous light source, a sulfur lamp, and combinations thereof, and has a dominant emissive wavelength is from about 400 nm to about 1600 nm. The source of narrowband, multichromatic electromagnetic radiation may further comprise a filter element for reducing the intensity of infrared radiation received by said tissue According to the continuous wave embodiment of the invention, the energy fluence received at the tissue is 1 J/cm2 or less. The energy fluence received at the tissue can be greater than 1 J/cm2 when the method further comprises cooling the tissue.
The method of the present invention may further comprise cooling the tissue to maintain a temperature of said tissue below the threshold for thermal injury and may further comprise maintaining the temperature of the tissue at or below 38xc2x0 C.